The present invention relates to carbonated beverages. More specifically, it relates to a dry carbonation source for use in preparing a carbonated beverage, the method for preparing this carbonation source, and a dry carbonated beverage concentrate.
The need for a dry carbonated beverage concentrate has existed for a long time. And, this need has been accentuated in recent years due to an increased awareness of the ecological limitations associated with canned and bottled carbonated beverages.
Early formulatory work on dry carbonated beverage concentrates predominantly utilized the carbonates and bicarbonates of sodium, potassium and ammonium as the sources of carbonation (e.g. Diller et al., U.S. Pat. No. 2,851,359). However, these carbonate sources are generally unacceptable when present in amounts sufficient to provide a desirable level of carbonation. Upon reaction with the acid in the beverage, whereby carbon dioxide is released, the corresponding sodium, ammonium and potassium salts are formed. The resultant, undesirable brackish taste can be alleviated to some degree by using a combination of these carbonates, but it generally persists thereby diminishing the palatability of the beverage.
The taste produced by the presence of calcium ions was found to be considerably more tolerable than that of the sodium or potassium ions. Accordingly, several workers have suggested employing calcium carbonate alone or in combination with other carbonates or bicarbonates to improve the palatability of carbonated beverages prepared from dry mixes (e.g. Diller et al. in U.S. Pat. Nos. 2,851,360 and 2,851,361, and Alther et al. in U.S. Pat. No. 2,603,569 and No. 2,639,238).
Calcium carbonate has not, however, been readily accepted. Because calcium carbonate is relatively insoluble, dry beverage concentrates employing it generally take excessively long periods of time to dissolve. Moreover, most commercial grades of calcium carbonate leave undesirable sediments when used in amounts sufficient to provide desirable levels of carbonation.
Carbon dioxide is released by a heterogeneous reaction between the calcium carbonate and the acid beverage solution. The reaction rate is dependent upon the exposed surface area of the calcium carbonate. The finest commercially available precipitated calcium carbonates have an average primary particle size of about 30 to 40 millimicrons. In reality, however, the primary particles are rarely present. In suspension, during preparation, the calcium carbonate particles tend to aggregate. These aggregates are only difficulty dissolved in the acid beverage solutions and cause a stubborn sediment. It has been found that even extensive and vigorous stirring does not effect solvation. Moreover, stirring must be kept to a minimum in intensity and duration so as not to evolve the CO.sub.2 already in solution.
To be acceptable, a dry carbonated beverage concentrate must be conveniently dissolved in ice water and provide an appealing appearing beverage. An important factor relating to the convenience of the beverage concentrate is the time which it takes for the beverage mix to completely dissolve in ice water. In general, for consumer acceptance as a convenience product, the beverage mix should fully dissolve within about two minutes and preferably about one minute. For most flavors, the beverage will not be appealing in appearance unless all cloud and sediment disappears to provide a completely crystal clear beverage. For flavors such as orange, lemon and grapefruit, however, the presence of a slight cloud may be considered desirable. But in no case is the presence of any noticeable degree of sediment desirable.